I am trying to use an input from Power Apps to create a new record in a CDS entity. Below is part of my Flow configuration.

I am initializing a string variable called Modified with the value coming from Power Apps. While testing, it is 3/31/2020. In the compose, the full Expression is
formatDateTime(variables('Modified'),'MM/dd/yyyy')
The Create a new record is not shown in full but in the Date field, I am just selecting Outputs from dynamic content.
The error I get is "An error occurred while validating input parameters: Microsoft.OData.ODataException: Cannot convert the literal '03-31-2020' to the expected type 'Edm.Date'...."
The date field is Date Only type and in Advanced options, behavior is Date only
I am not sure what's wrong with this. I have tried a few other variations of date formatting but haven't gotten it to work. Are there any other problems I'm missing with this?